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Dec. a, 1925. l 1,564,753 J. G. cAPsrAl-F 'REVERSAL PROCESS Filed Nov. 14. 1925 IN VEJV' TOR,

l Patented Dec. lv8, 1925. l

UNITED STATES PATl-:NT OFFICE.

`JOHN G. CAPSTAFF, `or ROCHESTER, NEW Yonx, `iissIeNor. To Ens'rMAN KODAK COMPANY, or nomineren, NEW YORK, A conronaTIoN or NEW YORK.

aEvE'nsAL raocnss. y f

. Application nled November 14, 1923. Serial No. 674,772.

To all whom t may concern: 7

Be it known thatl I, JOHN G. CAPSTAFF,

a subject of the Kin of'Great Britain, re`

`siding vat Rochester, '1n the county of Monroe and State of New York, have invented certain new and useful Improvements in Reversal Processes, of which the followingl is a full, clear, and exact specification.

This invention relates to a vphotographic A reversal'process. Such a process in general'v -includes the formation of a silver negative image by familiar methods inl asensitive emulsion, the removal of the silver image and .the transformation of the remaining sil! ver salts into a positive image, usual-ly of silver. Usually the bath or process by which the negative silver image is removed, known as a bleaching bath, has the J*property of desensitizing the remaining silver salts; and it is necessary to 'submit the emulsionlto a clearing bath, removing the products of the .bleachingbath and rendering the lsilver salts again sensitive. Moreover, the/usual bleaching bath has a greater or less tanning action on the' gelatine adjacent the original silver image, so that, it is impossibleto u tilize with theI final. positive silver image a process depending on a differential tanning action. i y

I have discovered that, by known baths, the negative silver image can be transformed or bleached, and that the resulting salts do not have the sensitivity that the remainimage in the usual way.

ing originalsilver. salts have, that 'the baths do"not have a tanning action on-the gelatine and that theyl do not have'a desensitizing action' on the remaining Original silver salts. 'I have utilized this Vdiscovery in a reversal process that comprises the following steps:

A. `The formation of a B. They transformation 'of'this 4into a sily lver halide image, there being still present ,the residual unaffected salts.

C. Exposure, to` light, vailtectilig the Aresidual but not the transformed salts and development of the affected salts, yieldinga positive silver image and halide image. 4

' Further steps depend on the particular use to which the plate or Iilm isjto be put,

and various processes including the above steps will be describedhereinafter.

Where possible the steps are illustrated,

a negative silver yly silver bromide.

negative silver plate with thesilver nega- In diderent em-l image transformed into apsilver bromide image; v

Fig. 3 shows the plate afterI the second development; v Fig. 4 shows the plate after removal of the bromide image; Fig. 5 shows the plate with the reversed image transformed into a dyed relief image;

Fig. 6 shows a double coated plate with dyed relief images made by my process;

Fig. 7 shows the plate with the reversed image 'transformed into adyeima e;

Fig 8 .shows a double coated p ate with dye images in both layers.

The several above mentioned steps will now be more fully described together with various other possible steps. f

' A.. The process is carriedout with a` sensitized element, referred to as a plate and comprising a support 1, `whicl1l may be of glass, pyrOXyIin, paper or other usual material, upon whichI is alayer 2, comprising an ordinary photographic emulsion of latine and sensitive-v silver salts, principal- This plate is ex-l posedl in any suitable photographic apparatus, such as 'a camera or printer,

iny any known developer which, iflater use is to be made of the tanning properties of gelatine, should. be free from tanning effects. There is thusformed in the layer 2 a silver image 3 vwhich is negative with respect to the light image, and there' will also be aresent a positive image 4 of the undeveloped silver salts.

ferricyan'ida grams; potassium bromide, 5 grams; water to 1 liter. The silver -ima e is transformed into one of silver bromi e, so that there are in the layer 2, two images of silver bromide one,I being positive and the other, 5,- being negative.

B. The plate is ythen submitted, after washing, tothefollowing bath: potassium Other bleaching baths may be used Which transform the image into silver bromide or silver chloride. Such baths are frequent'- ly mentioned in photogra hicliterature, but it was not heretofore own `that they rendered the salts produced by them apf .be considered as insensitive to 1ight,since' parently insensitive without affecting the sensitivity of vsalts 'of `the same nature' lin the same emulsion; nor Ihave they been proposed for processes such'as I now describe.

I contemplate as included within the scope of my invention any `bath having the properties described and rendering possible the process outlined.y y l I have found that this step should be carried out until the silver image .is'completely rehalogenized. If there lremain traces of thel silver ythese appear to actas nuclei vfor redevelopment. the process 1s obscure.

C.' The plate contalning the two vimages rlhe theory of is then exposedv for a short time to light. l'. havediscovered that'the image 5 is not.

nearl so sensitive to light as the image 4 le latter is, therefore, rendered developable, -While the image 'is'not.-

For practical purposes the image 5 may under an exposure' vsuiicient to render the image 4 completely developa'ble-it is aii'ected, if at all, to an exten'tthatis inappreciable in itsei'ect upon the process. When I referto it as insensitive 'it is to beunderstood that it may still 'have .some sensitlvity to Vvery pnolonged exposure, but as compared to the' 4 other image or the original lsalts such senmean that, r`While their sensitivity to light,l

v 40 Ais probably less thanitvvas origina11y',*they sitivity is very slight'indeed. When I refer to the original salts as'being unaffected I are still 'highly sensitive to llight and `are rendered develo'pable by short exposure to actinic light.

The plate is then submitted to any ordi-r nary developer, transforming image 4 into la positive silver image.` The process could be by development in ordinary light. `The l light could becontrolled in the manner speci- .'ed in .my Patent No. 1,460,703, granted July 3rd, 1923. The nature of the developer 1- is comparatively vimmaterial 4unless a later o step is to make luse of a tanning effect.

-A number of methods of-u'tilizing my invention Will be described"and`wvherea special type of developer is required it will vbe mentioned., v

D-1..The simplest way of proceeding by submitting the plate to the -usual ixin bath, removing, thesilver .bromide 5,6an

leaving the 'silver positive image 6. .As a reversal process this has the advantage-that no clearing bath after the bleach "is necessalg.

2. A second way -of 'proceeding is by' the/ wash-olf process. Infthis event,v the amarte rst developer must have been a non-tanning developer and the second one a tanning 1925, a1`id this method 'of utilizing my discovery maybe considered a modiiication or the'invention covered 4by'that patent. In this method the silver positive image 6 is obtainedv by a tanning developer and the v-upper untanned layer 5 is Washed oit in'hotv The silver may beA removed and .the'image dyed as. de-` scribed in that application, yielding a color-.

Water leaving a relief image.

ed relief image 7 on the support l.' This process is particularly useful with a double coated transparent support.

mentary color images are printed in registration and the resulting images suita ly dyed, there is obtained a two' color record developer. Suitable baths are described in my co-pending application, Serial No. 574",- '364, filed July 12, 1922, which has matured into'Patent, No.^1,525,7 66, granted Feb. 10,

If complewith dyed relief imagesS and 9, inv colors such as red and green.

D-. Another procedure is to submit the plate containing the silver image 6, either lbefore or after the removal of' bromide image 5 to a bleaching bath that willy render the gelatine diierentially dyeadsorbremoved. It is then -dyed yielding a vcolor Y.

image 10l infthe'layer 2. This process lis' also particularly applicable to a color proc-- ess carried out, on a double coa-ted transparentl support, yielding in layers 13 'and 14 registering images 11l and l2 of complementarycolor s uch as redf and green. The

color processes are completely describedin the above mentioned patents.

vantage over the method described in my patents that the' tanned'gelatineisnext the support instead of on the outer surface In 4the latter case the dye does not'easily penetrate thel tanned or hardened surface, 'which is affected more o1' less all over, to reach the themore -deeply aii'ected parts, whereas inI the presentl method the surfaceis'readily penetrable by the .dye.' I t will be not d that all o ftheodescribed methods of finishing `the process involve at.v

some point the step of'rernoving the rehalogenized, image 5.

of my invention all such modifications and equivalents as fall Within the .scopeof the appended claims.

It is ,obviousl that ,numerous .variations and applications of my invention -arepossible, and I 4cor'itemplate'z'w within: the scope' l '110, jfihisfaa; described method-hasni@ ad; I

i, image by reversal in a light sensitive. element containing a silvery image and a complementary image of sensitive silver salts, the steps of submitting the element to a bath that converts the silver image into a (liderent insensitive image Without renderingv the sensitive salts' insensitive, exposing; the element to light and developing the aii'ected sensitive salts to a Silver image. i I '2. ln a process of making a photographie image by reversal in a light sensitive element containing a silver image and acompleinenta'i'y image of sensitive silver salts, the steps of converting the silver :mage into an image of silver bromide, exposing the element to light and developing the adected sensitive salts into a silver image.

3. ln a process oi making a photographie image by reversal in a light sensitive eiement containing a silver image and a complementary image of sensitive silver salts, the steps of converting the silver imageinto an image of silver bromide, exposing the Yelement to light and developing the adected sensitive salts into a silver image, and thereafter treating the element to remove the iina'ectedsalts.

4. A process of making a photographic image in a light 'sensitive element containing a silver image and a complementary image in sensitive silver saltscthat comprises tlie transformation of the silver image into an image of insensitive silver halide without rendering the sensitive salts insenv sitive, exposing the element to light and All) thus rendering the sensitive salts developable, developing 'the sensitive silver salts to forni a silver image, and removing the insensitive silver salts.

5. A process of makingv a photographic image in a=light sensitive element containx' ing a` silver image and a complementary image in sensitive silver salts that comprises the complete halogenization of the silver image, without ailecting the first mentioned silver salts, exposing theV element to light and thus rendering the first mentioned salts developable and developing the affected salts to forma silver image.

6. A process vof making a photographic image in a light sensitive element containing a silver image and a complementary image in sensitive silver salts that comprises the complete halogenizatioii` of the silver image, Without aiecting the first mentioned silver salts, exposinvr 'the element to light and thus rendering the first mentioned salts developable, developing the affectedsalts to form a silver image and removing the iindeveloped halogenized image.

7. The process that comprises the ex der-the previously sensitive salts insensitive, i

exposing the element to light and developing the aected salts into a silver imagethat lies fat the bottomof the emulsion, and

removing the unadected salts. y

8. The vprocess of making a photographic print that comprises the exposure to alight image of an element comprising a photographically Lsensitive .gelatinosilver-halide emulsion, developing the affected salts in a hath that does not tan the gelatine, converting the developed image' into an insensitive silver halidevimage in a bath that does not tan the gelatine or render the previously sensitive salts insensitive, exposing the ele-4 ment to light and developing ,the adected salts into a silver image lying at the bottom of the emulsion, and illishing the print by 4a method that includes the removal of the insensitive salts, one of the steps' subsequent '10. The process of making a photographic print that comprises the exposure to a light image of an element ,comprising a photographically sensitive vgelatino-silver-Lhalide eniulsiondeveloping the afectedsalts into vasilver image by a bath that does not tan tlie gelatine, converting ,the silver image into 'a v.different insensitive image in a bath that does not tan-the gelatine nor render the unaffected salts insensitive, exposing the elei ment to light and developing the aected salts into a silver image lying at the bottom of the emulsion, and finishing the 'print by a method thatv includes the removal of the insensitive image, one of the steps subsequent to the convertin bath acting to tan the gelatine dierential and a subsequent step utilizin the tanne image.'

11. The p otographic process that com'-` -prises the exposure toa light image el anl element comprising a light sensitive gelatino-silver-halide emulsion, submittin l the element to a batlivthat develops the a ected salts'into a silver image without tanning the llO ' intoa silver image vWithout tanning T-,gelatine, submitting the element te a, beth that convertsthe silver image lntoan image of silver halide insensitive to light, without tannng the gelatine,` exposing'the element vto light and thus .rend'ing the sensitive `salts developable, submitting the element to a bath that develops the affected] silver salts the gelatine, submitting the element t a bath vthat converts the silver into e seluble salt 10` and tens the gelatine dierentially, submitting the element te a bathL that removes all the salts, and. then to a dye that is ziclsorloed.-

t0 the di'erentially hardened gelatine.

Signed at Rochester, New York, this 9th 15 

